Electropolishing apparatus



' Sept. 23, 1958 H. J. HACKENBURG 2,853,447

ELECTROPOLISHING APPARATUS Filed Aug. 3, 1956 v 5 Sheets-Sheet lINVENTOP HERMAN J HA C K E NBURG @cmkgw ATTORNEY p 1958 'H. J.HACKENBURG 2,853,447

ELECTROPOLISHING APPARATUS Filed Au 331956 0 3 Sheets-Sheet s as oINVENTOI? HERMAN J. HACKENBU/PG ATTORNEY United States Patent 2,853,447ELECTROPOLISHING APPARATUS Herman J. Hackenburg, Gillette, N. J.

Application August 3, 1956, Serial No. 601,923 Claims. (Cl. 204-214)This invention relates to apparatus for electrolytically polishingarticles comprising metals and/or alloys, and more specifically to ananode and cathode arrangement used in the apparatus for expeditiouslycarrying-on such polishing with a rotating barrel technique.

Heretofore, electropolishing of metallic articles has been generallyperformed in stationary apparatus. Prior attempts to perform suchelectropolishing in rotating barrels have been only moderatelysuccessful. The absence of satisfactory results in the use ofelectropolishing apparatus of the barrel type may have been due in part,at

least, to the specific compositions of the electrolytic baths that werethen employed. In the rotating barrel technique, the anode and cathodewere usually fixed in relative size so that adjustments in the techniquewere confined to variations of the composition of the electrolytic bathin an endeavor to promote efliciency and .quality. For the most part inprior art electropolishing apparatus, the relative size of the anode andcathode was fixed in a unitary structure thereby permitting adjustmentonly of the electropolishing techniques in respect to the specificcomposition of the electrolytic bath at a given moment.

The foregoing operation often resulted in unnecessary expenditures oftime and money in an area which tended to effect a partial but not anentirely satisfactory movement in the technique. In instances where themetallic articles polished electrolytically were not intended forexposure to public view in their use, a mediocre appearance wastolerable. In those instances, however, where such metallic articleswere intended for, continuous exposure to public view, only metallicarticles electropolished to optimum appearance with long life wereacceptable. In the latter instance, it frequently happened that a largenumber of rejects increased the overall electropolishing cost touneconomical proportions.

Accordingly, the present invention contemplates electropolishingapparatus provided with cathodes adaptable for expeditious adjustment inreguard to size, shapeand location and usable in a rotating barreltechnique.

An object of the invention is to promote the efficiency ofelectrolytical polishing of metallic articles effected in a rotatingbarrel.

Another object is to improve the quality of the electrolytical polishingof metallic articles achieved in a rotating barrel.

A further object is to provide a facile control for anelectrolytical-polishing technique using a rotating barrel.

Still another object is to provide expeditiously the optimum ratiobetween the exposed surfaces of the cathode and anode mounted on arotating barrel used in electrolytical-polishing apparatus.

Still another object is to provide an arrangement for expeditiouslycontrolling the ratio between the exposed surfaces of the anode andcathode afiixed to a rotating barrel used in an electrolytical-polishingapparatus.

In a specific embodiment for electrolytically polishing metallicarticles with improved eflic'iency and quality effected with a bath ofsuitable electrolyte, a source of 2,853,447 Patented Sept. 23, 1958 'icedirect current voltage having positive and negative-terminals and aperforate non-conductive barrel rotatable in the electrolytic bath andhaving a perforated closed end and an open end, the present inventioncomprises a perforateanode disposed interiorly of the barrel adjacentthe perforated closed end thereof in contact with the metallic articlesto be electropolished, a rotatable shaft forming an electricalconnection for the positive terminal of the voltage source, anon-conductive yoke having one end mounted on the shaft and an oppositeend attached to the anode and closed barrel end, an electricalconnection included interiorly of the yoke butexposed at both the oneand opposite ends thereof in such manner that the exposed electricalconnection at the one end is in electrical contact with the shaft whilethe exposed electrical connection at the opposite end is in electricalcontact with the anode, and a plurality of discrete elongated cathodesmounted in spaced relation on the periphery of the barrel and connectedtogether to'constitute a unitary cathode, certain ones of the cathodesbeing turned-in over approximately one-half of the open end of thebarrel and provided with a common electrical termination which isadjacent to but spaced from an end of the shaft, and means connected tosuch termination and coaxially mountedwith but electrically insulatedfrom the shaft to constitute an electrical connection for the negativeterminal of the voltage source. a,

A feature of the present invention is that the rotating barrel isprovided with such physical dimensions that the barrel including theanode and work mounted therein may be readily mounted upon and removedfrom the electrolytic tank by a single workman. I

Another feature is that the cathodes being spaced on the outer'periphery of the rotating barrel containing the work may be soexpeditiously adjusted in shape, number and size that an optimum ratioof cathode surface to anode surface may be readily provided, withoutdisturbing the electrolytic bath.

Still another feature is that the peripheral disposition of theelongated cathodes enables them to be interchanged substantially withminimum mechanical difficulty withoutdisturbing the electrolytic bath.

A further feature is that the mounting of the anode interiorly of therotating barrel on the perforated closed end thereof provides a firm andcontinuous contact with the positive terminal of the voltage source atall times during the rotation of the barrel.

Still another feature is that the metallic articles to beelectrolytically polished are positioned within the rotating barrelalways in a facile, continuous and efiicient electrical contact with theanode within the electrolytic bath during the rotation of the barrel.

The invention will be readily understood from the following descriptionwhen read together with the accompanying drawing in which:

Fig. 1 is a perspective view of a specific embodiment of the invention;

Fig. 2 is a perspective view of a portion of the invention shown in Fig.1;

Fig. 3 is an elevational view with cutaways of a portion of theinvention shown in Fig. 1; i a

Fig. 4 is a schematic circuit showing the electrical connections for theinvention illustrated in Fig. l; and

Fig. 5 is a partial elevational view taken along line 5-5 in Fig. 1. i

As illustrated in Fig. l, a bath 10 of suitable electrolyte is containedina tank 11 mounted on a floor, not shown, in a conventional manner.Shelf 12- made of acid-resistive material and mounted interiorly of thetank at an upper end of one side thereof is provided with an aperture,not shown, for receiving a reduced end 13 of a swivel 14 shown in Figs.1 and 2. An upper end of the swivel includes a pivot for rotatablymounting a frame 16, and contains a peripheral recess 17 for a purposethat will laterappear. The recess 17 is adapted to receive one end ofaplunger 19 which is slidably mounted in an elongated slot 20 providedinteriorly of frame 16. The plunger has an opposite end coaxiallymounted with a coiled compression spring 21. p g

A finger grip 22 attached to a central portion of the plunger projectsthrough an opening 23 provided in the frame and serves to effectslidable movements of the plunger in slot 20 for a purpose that willpresently appear. When the plunger is withdrawn from recess 17 of theswivel, the frame'is disposable at an oblique angle relative to ahorizontal surface of shelf 12 as shown in Figs. 1 and 2. When theplunger is disposed in recess 17 of the swivel, the frame will bepositioned approximately in a a vertical manner as indicated by thedot-dash lines in Fig. 1. This positioning of the frame is achieved bythe location of recess 17 in an uppermost peripheral portion of theswivel. It will be understood that compression spring 21 retains theplunger in recess 17 in which theplunger may be disposed at a given timewhereas a withdrawal of the plunger against the force of the compressionspring by the finger grip from either recess enables the frame to berotated in a clockwise or counter-clockwise direction relative to shelf12, depending on the initial position of the frame, to either theoblique or vertical positionfor a purpose that will be presentlyexplained. v

In accordance with a specific embodiment ofthe present invention, itwill be'seen in Figs. 1 and 2 that the frame positioned obliquelyrelative to shelf 12 or 'thehorizontal surface of the electrolytic bathhas its free end bent approximately at 90 degrees andterminatedsubstantially in an inverted U-shaped portion 31. Of the latter, legs 32and 33 support suitable ball bearings '34 and 35, respectively, for oneend of a sha'ft'36. On the latter shaft adjacent bearing 34 is fixedlymounted'worm gear 37 adapted to engage worm 38 in a manner and for apurpose that will be subsequently mentioned.

Referring to Fig. 3, the free end of shaft 36' is formed with anintegral coaxial flange 42 adapted to ride against an inner surface ofleg 33. This shaft is also formed with an integral portion 43 extendingcoaxially therewith and normally to'fiange42. The shaft portion 43 isprovided with a rectangular outer shape'a'nd an interior rectangularopening for purposes that will'presentlyappear. Positioned externally ofshaft portion 43 and adjacent flange 42 is an insulating collar 44formed with adepressed central portion 45 carrying collector ring 46 'ofelectrically conductive material. This'r'im' is secured in position oncollar 44 by an elongated "screw 47 which also serves a further purposethat will'be "subsequently mentioned.

Yoke 48 in Fig. 3 comprises an-insulating material preselected formechanical strength and having positioned axially therewithinelectrically conductivecores 51 and 5111 which are formed to terminateat certain corresponding ends in an electrically conductive ring 52adjacent shaft portion 43. Ring 52 has an axial rectangular openingwhich accommodates therein the corresponding rectangular outer shape ofshaft portion 43 and thereby enables yoke 48 to be mounted-on shaftportion 43 adjacent to insulating collar 44. Ring 52 is secured toinsulating collar 44 by a plurality of screws 49, 49 extending through ametallic plate 50 and anchored in the latter insulating collar.Corresponding opposite ends of cores 51 and 51a are also formed toterminate in a circular plate 53 formed'with an integral annular portion53a.

A perforate barrel 54 comprising an insulating and acid-resistivematerial preselected for mechanical strength has a perforated closed endand an 'open end as shown in Figs. 2 and 3; A perforate anode 55 isdisposed on the inner surface of the closed perforate end of the barrel,and both the anode and latter barrel end are 4 secured to the innersurface of annularportion-53a-by a plurality of metallic andacid-resistive screws 56, 56. These screws provide an electricalconnection via yoke 48 between anode 55 and shaft 36 for a purpose thatwill later appear.

As shown in Figs. 1 and 2, worm gear 37 is meshed with worm 38 which isformed integrally with a shaft 57 whose opposite ends are-rotatablysupported in suitable bearings provided in bent-in and parallel sides 58and 59 of a bracket 60. This bracket is mounted on a shelf 61 providedatone end and on the top of tank 11 and comprising a suitable insulatingand acid-resistive material such, for example,-as specially treated woodor the like. The worm shaft 57 is connected via clutch 62 and drivingmechanism 63 to electric motor 64. A fingeractuated switch 65 controlsthe energization of the motor through electrical cable 66 fromaconventional commercial AI-C. supply, not shown.

Referring to Figs. 1 and 5, it will be seen that shaft 36 restsrotatably on a bearing provided by the sloping inner sides of the twolegs of a bifurcated member '69. This member is vertically adjustable onbracket 60 by means of a pair of'vertically elongated slots 70, 70provided in member 69 and a pair of screws 71, 71 mounted in bracket 60and projecting through the slots. Thus, the shaft 36 may be varied inposition as desired substantially in a vertical direction byappropriately. adjusting the positions of the slots 70, 70 of member 69on associatedscrews 71, 71. This will tend to control the amount ofmeshing between gears 37 and 38 and thereby establishafirm mechanicaland electrical. connection therebetween for. a purpose that will laterappear.

Asshown in Figs. 1 through 4, a circuit connecting the positive terminalof direct-'currentvoltage source 73 in Fig. 4 to anode 55in Figs. 2.iand3i'may.be:traced-.-as follows: in-sequence, lead 72 connecting thepositive .terminal of voltage source 73 to side-59 ofbracketi61, worm38, worm gear 37, shaft 36, flange-42, shaft portion- 43, terminatingring 52 of yoke- 48gcores 51' and 51a, terminating plate 53, annularportion 53a, screws 56, 56 and anode 55. This circuit servesa'purposethat will be hereinafter pointed out. In the-'afore tra'cedcircuit it will be noted that clutch 62 in Fig. '1 insulateselectrically voltage source 73' from driving mechanism 63 and motor 64attached thereto. It-will be understood that voltage source 73 provides'a direct-cu'rrentroltage of preselected magnitude suitablefor'eifectingthe electrolytical electropolishing hereinafter described,and variable in magnitude by a-conventionally adjustableresistor, notshown, if so desired. A plurality of elongatedmectangular "discretecathodes 75, 75 of electrically conductivematelial such as copper orthelike is disposed in spacedrelation about'the outer periphery of thebarrel in such. manner" that one side-of smaller dimension is disposedsubstantiallywangentially to the periphery 'of thebarr'el and the axesof longer dirnensions are disposed substantiallyrin parallel relationwith the axis of rotation of the barrel; as 'illus' trated in Figs. 1,2: and 3. For this purpose, rims 76 and 77 are rigidly affixedexternally to the opposite ends ofthe barrel; and right-angle cut-outportions 73 are provided at opposite corresponding ends ofeachcathode.These cut-out portions enable the cathodes tofit snuglyand firmly onthebarrel-rims and thereby to be disposed in length substantiallycoextensively withthe. lengthof the barrel.

Adjacent cathodes are held in spaced relationby a pinrality of spacers79, 79 made of hollow electrically insulating and acid-resistivematerial. The spacers are mounted coaxially-on a pair of annular tierodsfitl and 81 made of copper or the like, which comprises an"electrically conductive material, and disposed aboutthe outer peripheryof the barrel inspaced relation along the rotational axis thereof. Itwill be understood that the cathd odes 75, 75 are provided with suitableholes 68, 68 as shown in Fig. 2 to accommodate the tie rods with a tightfit to constitute a suitable electrical connection for a purpose thatwill be presently mentioned.

The free ends of each of tie rods 80 and 81 are threaded and disposed inopposed relation on opposing surfaces of cathodes 82 and 83 whichcomprise the integral sides of a channel 84 made of copper or the likewhich comprises an electrically conductive material, as seen in Figs. 2and 3. It will be apparent that right-angle cut-out portions 78 are alsoprovided on the opposite corresponding ends of cathodes 82 and 83whereby the latter are enabled to fit snugly and firmly against thebarrel rims 76 and 77. Nuts 85, 85 are mounted on the threaded opposingends of the tie rods. This secures all cathodes together firmly as aunitary cathode structure adjacent the outer periphery of the barrel, asthe latter is rotated for a purpose that will be later mentioned.

As illustrated in Fig. 2, a preselected group of cathodes 75 havecorresponding end portions 75a extended and turned-in over the edge ofthe barrel in a radial direction toward the axis of rotation thereofover an area equal substantially to one-half of the open end thereofwhile the remaining one-half of the open barrel end remains uncovered orunobstructed for a purpose that will presently appear. A plurality offins 90, 90 is disposed adjacent the open barrel end in proximity ofturned-in portions 75a, each fin being made of copper or the like andcomprising an electrically conductive material. Of these t'ached to anoutermost end of one turned-in portion 75a and .an opposite end formedin an angle portion 900. Similarly a second fin 90d has one end suitablyconnected to a turned-in portion 75a of cathode 83 and an opposite endformed in an angle portion in a manner like that of angle portion 900.

Thus, each of the remainder of fins 9t), 90 has one end attached to oneturned-in portion 75a and an opposite end formed generally like angleportion 90c. All of the corresponding opposite ends of fins 9b, 90, i.e. those formed generally like angle portions 900 are mechanically andelectrically secured together in a firm unitary engagement via screws91, 91 to constitute a common electrical termination for all cathodes75, 75. This commontermination is disposed substantially adjacent to butspaced from the free end of shaft portion 43, on which yoke 48 ismounted and includes at least one point coincident with the axis ofrotation of the barrel. While some cathodes are composed of the twoparts above described, it will be evident that they could equally asWell be formed of one part. It will be thus apparent that the remainingone-half of the open end of the barrel is unobstructed to permit loadingand unloading of work, i. e., the articles to be electrolyticallypolished, in a manner that will be subsequently described. Anelectrically conductive strap 92 connects one of the screws 91 of thecommon termination and thereby all fins and cathodes to a point lyingbetween the head of screw 93 and an electrically insulating strip 94disposed adjacent metallic plate 50, as seen in Fig. 3. In the latterfigure, screw 93 passes through a hole, not shown, in insulating strip94 and is anchored in one end of a metallic insert 95 of rectangularconfiguration positioned in an accommodating rectangular coaxial openingformed in a rectangular sleeve 96 of electrically insulating material,both the latter insert and sleeve being positioned internally of therectangular opening formed interiorly of shaft portion 43, as previouslymentioned. An opposite end of the metallic insert 95 serves to anchorthe free end of elongated screw 47 which provides a suitable electricalconnection between metallic insert 95 and collector ring 46.

It will be understood that screw 47 passes through a hole, not shown, inshaft portion 43 of such size and shape as to preclude a contact betweenthe screw and shaft portion. Also, it will be understood that screw 47and insert 95 are electrically insulated from any contact with shaftportion 43 and/ or yoke 48. Thus, it will be apparent from theafore-described structure that all cathodes 75 are connected in anelectrical circuit to collector ring 46.

The collector ring 46 is frictionally engaged substantially ondiametrically opposite points by a pair of fingers or brushes 97, 97comprising flexible metallic material and secured to an electricallyinsulating strip 98 which is suitably afiixed to the shelf 61 on thetank. A metallic clip 99 connects the fingers 97, 97 via lead 100 and asingle pole single throw switch 102 to the negative terminal of voltagesource 73. Each of brushes 97 is formed with an integral turned-outportion 101, Fig. 2, to permit collector ring 46 and the afore-describedmounting therefor to pass expeditiously into and out of engagement withthe brushes 97, 97 as the mounting frame 16 is rotated on its pivot 15for a purpose that will presently appear.

In operation of the specific embodiment of the invention asafore-described, it will be understood that initially switches 65 and102 are actuated by a workman to disconnect the A.-C. supply from motor64 and the D.-C. voltage source 73 from the associated anode andcathode, respectively; and that finger grip 22 has been appropriatelyadjusted by the workman to permit mounting frame 16 to rotate its pivot15 in a counter-clockwise direction to the vertical position shown bythe dot-dash lines in Fig. 1 and thereby disengage worm gear 37 fromworm 38, as the collector ring 46. is withdrawn from contacting brushes97, 97.

This will enable the workman to withdraw reduced end 13 of swivel 14from shelf 12 and thereby carry away the barrel from the tank ofelectrolyte. This may be expeditiously achieved for the reason that thebarrel has an outside diameter of the order of eight inches and andoverall length of approximately twelve inches. The

a frame and barrel are then carried to a suitable point for loading workthereinto. The bath of electrolyte will now be assumed to comprisechemical constituents suitable for the electrolytic polishing of workconsisting of small metallic articles, such bath being of a type knownin the art.

Assuming further that the barrel is initially empty, it can be loaded toa suitable amount by putting thereinto the articles to beelectrolytically polished through the unobstructed one-half of the openend of the barrel which was hereinbefore mentioned. Then, the reducedend 13 of swivel 14 is re-inserted into the aperture of shelf 12whereupon mounting frame 16 is returned to the vertical position shownby the dot-dash lines in Fig. 1. Next, finger grip 22 is appropriatelyadjusted in the manner above-mentioned by the workman to permit mountingframe 16 to rotate in a clockwise direction on its pivot 15 to theangular position shown in full lines in Fig. 1.

\ Now, the articles in the barrel are disposed in mechanical andelectrical engagement with each other and with the anode 55 toconstitute eifectively a unitary and composite anode (positive terminal)for the electro-polishing system hereinbefore described.

This will enable worm gear 37 and collector ring 46 to re-engage worm 38and fingers 97, 97, respectively. Closure of switch 102 will connect theanode and cathode to the positive and negative terminals, respectively,of voltage source 73. Finally, switch 65 is operated to connectthe'A.-C. supply to motor 64 whereupon the barrel is rotated with theanode and work in electrical contact with each other in the electrolyticbath at a preselected R. P. M. speed. Thus, the articles disposed in theinterior of the barrel are electrolytically polished in the well-knownmanner.

An addition to or a subtraction from the number of cathodes positionedexternally of the barrel in the manner above-described enables a facileadjustment to an.

7 optimum value of the ratio of cathode surface to the surface anode,the latter surface including both anode plate 55 and articles to beelectrolytically polished. A further adjustment of such ratio may alsobe expeditiously achieved by varying the physical size of the individualcathodes, as well as combining cathodes of different physical sizes inthe array disposed peripherally externally of the barrel as shown inFigs. 1 and 2. Moreover, it will be I apparent that the articles remainin electrical contact With-each other and with the anode at all timesduring the rotation of the barrel.

It will be understood that while the invention has been described withreference to a particular embodiment, other embodiments will be evidentto those skilled in the art.

What is claimed is:

1. In apparatus fo-r'electropolishing work comprising a tankadapted tocontain a bath of electrolyte, a source of direct current voltage, arotating shaft connected to one terminal of said source, a perforatenon-conductive barrel having a closed end and an open end for holdingsaid work, a perforate anode positioned interiorly of said barreladjacent said closed barrel end in contact with said work, anon-conductive support, an electrical conductor mounted interiorly ofsaid support and exposed at two spaced surface portions of said supportto provide two spaced acreas for electrical connections, one of saidareas being electrically connected through said closed barrel end tosaid anode and thereby mounting said barrel on said support, the secondof said areas-being connected to one end of said shaft for connectingsaid anode to said shaft and mounting said support on said shaft, saidmountingof said support on said one shaft end also mounting said barrelcoaxially with said shaft for rotating said barrel, anode and work insaid bath of electrolyte While at the same time connecting said anode tosaid one terminal of said source, a plurality of discrete cathodesmounted in spaced relation on an external periphery of said barrel andelectrically connected together to constitute a unitary cathode, saidcathodes comprising discrete elongated members extending substantiallycoextensively with the length of said barrel and having their longeraxes disposed substantially in parallel relation with the rotationalaxis of said barrel, and electrically conductive means mounted on saidone shaft end and elec trically insulated therefrom, said last-mentionedmeans comprising an electrical connection mounted interiorly of said oneshaft end and terminating in two electrical contacts mounted in spacedrelation exteriorly on said shaft, one of said contacts being mounted onthe face of said one shaft end and permanently electrically connected tosaid unitary cathode, and the second of said contacts being mounted onthe periphery of said one shaft end and being slidably electricallyconnected to another terminal of said source for electrically connectingsaid unitary cathode to said last-mentioned terminal during the rotationof said barrel, anode and work in said bath of electrolyte by saidshaft.

2. The apparatus according to claim 1 in which at least one of saidcathode members has an end turned-in over said open end of said barreland terminated in a section substantially coincident with said face ofsaid one shaft end but spaced therefrom, said one contact beingpermanently electrically connected to said last-mentioned section andthereby to said unitary cathode.

3." The apparatus according to claim 1 in which the ends of apreselected group of adjacent cathode members of said plurality ofcathode members are turned-in over said open end of said barrel for anarea equal approximately to one-half of said last-mentioned open barrelend, said turned-in ends terminating in a common electrical sectionsubstantially coincident with said face of said one shaft end but spacedtherefrom, said one contact being permanently electrically connected tosaid common section and thereby to said unitary cathode.

4. The apparatus according to claim 1 in which said elongated cathodemembers have rectangular cross-seotions and are mounted on the externalperiphery of said barrel with sides of the smaller dimension engagingrespectively different portions of the external periphery of saidbarrel.

5. The apparatus according to claim 4 in which said elongated cathodemembers have sides of the larger dimension extending from therespectively different portions of the external periphery of said barrelsubstantially in radial directions relative to the rotational axis ofsaid barrel.

6. In apparatus for electropolishin-g work comprising a tank adapted tocontain a bath of electrolyte, a source of direct current voltage havinga positive terminal and a negative terminal, a perforate anode, aperforate nonconductive barrel having a closed perforate end and beingopen at the other end for holding said work, said anode being positionedinteriorly of said barrel adjacent said closed end thereof forengagement with said work, a rotatable shaft electrically connected tosaid positive terminal, a non-conductive yoke including an electricallyconductive core exposed on two different surface portions of said yoketo constitute two spaced areas for electrical connections on said yoke,said barrel being mounted on said yoke, one of said last-mentioned twoareas being electrically connected through said closed end of saidbarrel with said anode and thereby holding said barrel mounted on saidyoke, the other of said last-mentioned two areas being connected to oneend of said shaft for electrically connecting said anode to saidpositive terminal and mounting said yoke on said one shaft end, saidlast-mentioned mounting of said yoke serving to mount said barrel andanode coaxially with said shaft for rotating said barrel, anode and workin said bath of electrolyte, a plurality of discrete cathodes mounted inspaced relation on an external periphery of said barrel and connectedtogether electrically to constitute a unitary cathode, certain adjacentcathodes of said plurality of cathodes having end portions turned-in,over the open end of said barrel for an area equal approximately toonehalf of said open end of said barrel, said turned-in end portionsterminating in a common electrical portion disposed adjacent to butspaced from said one shaft end so that substantially the remainingone-half of the open end of said barrel permits the insertion of saidwork into said barrel and the removal of said work therefrom, andelectrically conductive means mounted on said one shaft end andelectrically insulated therefrom, said lastmentioned means comprisingsubstantially right-angle conductive means mounted interiorly of saidone shaft end, said last-mentioned means having one end terminating onthe face of said one shaft end and the opposite end terminatingcoextensively with the periphery of said one shaft end, saidterminations of said one and opposite ends of said right-angle meansbeing mounted substantially coaxially with said shaft, saidlast-mentioned terminating one end of said conductive means beingpermanently electrically connected to said common cathode portion, andsaid last-mentioned terminating opposite peripherally coextensive end ofsaid conductive means being slidably electrically connected to saidnegative terminal for electrically connecting said unitary cathode tosaid last-mentioned terminal during the rotation of said barrel andanode and work in said bath of electrolyte by said shaft.

7. The apparatus according to claim 6 in which said plurality ofdiscrete cathodes comprises a plurality of discrete elongated membershaving rectangular cross-sections and mounted on an external peripheryof said barrel with narrow sides engaging respectively differentperipheral portions of said barrel and with Wider sides extending fromthe respectively different peripheral portions of said barrelsubstantially in radial directions relative to rotational axis of saidbarrel, said certain adjacent cathodes comprising portions substantiallycoextensive with the length of said barrel and said turned-in endportions disposed substantially at right angle relative to saidlast-mentioned coextensive portions for an area approximating one-halfof said open end of said barrel, and the remaining cathodes of saidplurality of cathodes being substantially coextensive with the length ofsaid barrel so that substantially the remaining one-half of said openend of said barrel permits the insertion of said work into said barrelthrough said last-mentioned onehalf open barrel end and the removal ofsaid work from said barrel through said last-mentioned one-half openbarrel end.

8. The apparatus according to claim 6 in which said terminating oppositeperipherally coextensive end of said right-angle means comprises anelectrically conductive collar mounted coaxially with and electricallyinsulated from the periphery of said end of said shaft, and whichincludes resilient means electrically frictionally engaging said collarduring the rotation of said shaft for electrically connecting saidunitary cathode to said negative terminal.

9. Apparatus for electropolishing Work comprising a tank adapted tocontain a bath of electrolyte, a source of direct current voltage havingpositive and negative terminals, a perforate anode, a perforatenon-conductive barrel having a closed perforate end and being entirelyopen at the opposite end for holding said work, said anode beingpositioned interiorly of said barrel on said perforate end thereof andhaving said work in engagement with said anode, a rotatable shaftelectrically connected to said positive terminal of said source, anonconductive yoke including an electrically conductive core exposed attwo spaced portions on said yoke' to constitute two spaced electricalconnection areas, said barrel being mounted within said yoke adjacentone of said two areas, said last-mentioned one area being electricallyconnected through said closed end of said barrel to said anode andthereby holding said barrel mounted on said yoke, the other of said twoareas being formed with an axial opening of preselected configurationfor accommodating a corresponding configuration formed on one end ofsaid shaft to electrically connect said anode to said shaft and therebyconnect said anode to said positive terminal, said last-mentionedconnection also serving to mount said yoke on said shaft and therebymount said barrel coaxially with said shaft, said shaft rotating saidbarrel, anode and work in said bath of electrolyte while at the sametime continuing the connection of said anode to said positive terminal,a plurality of discrete elongated cathodes positioned in spaced relationon an external periphery of said barrel and electrically connectedtogether to form a unitary cathode, said cathodes having at least alength substantially coextensive with the length of said barrel, apreselected group of said cathodes having corresponding ends turned-inover the open end of said barrel in a radial direction toward the axisof rotation of said barrel, a plurality of electrically conductivemembers having corresponding ends connected to said cathode turned-inends and having opposite ends joined together to form a commonelectrical termination for said unitary cathode adjacent to but spacedfrom said one shaft end, said members and cathode turned-in endscovering an area equivalent substantially to one-half of said open endof said barrel so that the remaining one-half of said last-mentionedopen barrel end is available for loading work therethrough into saidbarrel and unloading work therethrough from said barrel, electricallyconductive means mounted on said one shaft end and electricallyinsulated therefrom, said last-mentioned means comprising a collectorring mounted externally of and coaxially with said shaft, an electricalcontact mounted on the face of said one shaft end, and an electricalconductor mounted interiorly of said one shaft end for electricallyconnecting said collector ring and contact, an electrically conductivestrap for connecting said common termination to said contact, and a pairof brushes disposed in spaced relation on the periphery of saidcollector ring for electrically slidable engagement therewith, saidmembers, strap, contact, conductor, collector ring and brusheselectrically connecting said unitary cathode to said negative terminalof said source during the rotation of said barrel, anode and work insaid bath of electrolyte by said shaft.

10. The apparatus according to claim 9 which includes a driven gearmounted on the free end of said shaft, a driving gear meshed with saiddriven gear, said shaft being electrically connected through said drivenand driving gears to said positive terminal of said source, and a motormechanically coupled to said driving gear for driving said driven gearand thereby rotating said shaft, said motor being electrically insulatedfrom said last-mentioned positive terminal of said source.

11. The apparatus according to claim 10 in which said driving gear andpair of brushes are mounted on said tank, and which includes a mountingframe having one end connected to said shaft and an opposite endpivotally mounted on said tank, said mounting frame being movable onsaid pivoted opposite end thereof in one direction for engaging saiddriven gear and collector ring with said driving gear and pair ofbrushes, respectively, to dispose said barrel, anode and work in saidbath of electrolyte, said mounting frame being movable on said pivotedopposite end thereof in an opposite direction to disengage said drivengear and collector ring from said driving gear and pair of brushes,respectively, to withdraw said barrel, anode and work from said bath ofelectrolyte, and adjustable means mounted on said tank for controllingthe amount of meshing between said driven and driving gears to provide afirm mechanical and electrical engagement therebetween.

12. The apparatus according to claim 11 in which said pivotally mountedopposite end of said mounting frame is detachable from said tank wherebysaid barrel is disengaged from said tank for the loading of said workinto said barrel and the unloading of said work therefrom through saidremaining one-half open end of said barrel.

13. The apparatus according to claim 1 in which said electricalconnection in said one shaft end has substantially a -degreeconfiguration.

14. The apparatus according to claim 13 in which said electricalconnection of 90-degree configuration in said one shaft end comprisestwo legs, one leg being disposed substantially coaxially with said oneshaft end and the other leg being positioned substantially normally tosaid one leg.

15. The apparatus according to claim 14 in which said one contact ismounted on the free end of said one leg on the face of said one shaftend, and said second contact is attached to the free end of said otherleg and mounted coextensively with the periphery of said one shaft end,said one and second contacts being mounted coaxially with said one shaftend.

References Cited in the file of this patent UNITED STATES PATENTS981,004 Reid Ian. 10, 1911 1,254,046 King Jan. 22, 1918 1,522,422Daniels Jan. 6, 1925 1,525,271 Daniels Feb. 3, 1925 1,583,930 Iantz eta1 May 11, 1926 1,936,382 Daniels Nov. 21, 1933

1. IN APPARATUS FOR ELECTROPOLISHING WORK COMPRISING A TANK ADAPTED TOCONTAIN A BATH OF ELECTROLYTE, A SOURCE OF DIRECT CURRENT VOLTAGE, AROTATING SHAFT CONNECTED TO ONE TERMINAL OF SAID SOURCE, A PERFORATENON-CONDUCTIVE BARREL HAVING A CLOSED END AND AN OPEN END FOR HOLDINGSAID WORK, A PERFORATE ANODE PLOSITIONED INTERIORLY OF SAID BARRELADJACENT SAID CLOSED BARREL END IN CONTACT WITH SAID WORK, ANON-CONDUCTIVE SUPPORT, AN ELECTRICAL CONDUCTOR AMOUNTED INTERIORLY OFSAID SUPPORT AND EXPOSED AT TWO SPACED SURFACE PORTIONS OF SAID SUPPORTTO PROVIDE TWO SPACED ACREAS FOR ELECTRICAL CONNECTIONS, ONE OF SAIDAREAS BEING ELECTRICALLY CONNECTED THROUGH SAID CLOSED BARREL END TOSAID ANODE AND THEREBY MOUNTING SAID BARREL ON SAID SUPPORT, THE SECONDOF SAID AREAS, BEING CONNECTED TO ONE END OF SAID SHAFT FOR CONNECTINGSAID ANODE TO SAID SHAFT AND MOUNTING SAID SUPPORT ON SAID SHAFT, SAIDMOUNTING OF SAID SUPPORT ON SAID ONE SHAFT END ALSO MOUNTING SAID BARRELCOAXIALLY WITH SAID SHAFT FOR ROTATING SAID BARREL, ANODE AND WORK INSAID BATH OF ELECTROLYTE WHILE AT THE SAME TIME CONNECTING SAID ANODE TOSAID ONE TERMINAL OF SAID SOURCE, A PLURALITY OF DISCRETE CATHODESMOUNTED IN SPACED RELATION ON AN EXTERNAL PERIPHERY OF SAID BARREL ANDELECTRICALLY CONNECTED TOGETHER TO CONSTITUTE A UNITARY CATHODE, SAILDCATHODES COMPRISING DISCRETE ELONGATED MEMBERS EXTENDING SUBSTANTIALLYCOEXTENSIVELY WITH THE LENGTH OF SAID BARREL AND HAVING THEIR LONGERAXES DISPOSED SUBSTANTIALLY IN PARALLEL RELATION WITH THE ROTATIONALAXIS OF SAID BARREL, AND ELECTRICALLY CONDUCTIVE MEANS MOUNTED ON SAIDONE SHAFT END AND ELECTRICALLY INSULATED THEREFROM, SAID LAST-MENTIONEDMEANS COMPRISING AN ELECTRICAL CONNECTION MOUNTED INTERIORLY OF SAID ONESHAFT END AND TERMINATING IN TWO ELECTRICAL CONTACTS MOUNTED IN SPACEDRELATION EXTERIORLY ON SAID SHAFT, ONE OF SAID CONTACTS BEING MOUNTED ONTHE FACE OF SAID ONE SHAFT END AND PERMANENTLY ELECTRICALLY CONNECTED TOSAID UNITARY CATHODE, AND THE SECOND OF SAID CONTACTS BEING MOUNTED ONTHE PERIPHERY OF SAID ONE SHAFT END AND BEING SLIDABLY ELECTRICALLYCONNECTED TO ANOTHER TERMINAL OF SAID SOURCE FOR ELECTRICALLY CONNECTINGSAID UNITARY CATHODE TO SAID LAST-MENTIONED TERMINAL DURING THE ROTATIONOF SAID BARREL, ANODE AND WORK IN SAID BATH OF ELECTROLYTE BY SAIDSHAFT.